Please, find below a new contribution about crustaceans ectoparasities and epibionts of humpback whales in the Colombian Pacific.  If you would like an electronic pdf copy, please contact me (isabel_c_avila@yahoo.com). Abstract:  We  recorded  three  species  of  crustacean  ectoparasites  and epibionts in two calves and four adults of humpback whale (Megaptera novaeangliae)  that  in  the  breeding  season  2010  visited  PNN  Gorgona and  Bahía  Málaga,  Colombian  Pacific:  the  amphipod Cyamus  boopis and the barnacles Coronula diadema and Conchoderma auritum. These crustaceans adhere to calves and adults and are present in the caudal fin, dorsal fin, back of the body (near the blowhole) and ventral side of the lower jaw. Ectoparasites and epibionts recorded here may influence the movement, feeding and behavior of whales. We found a calf of no more than three months of age with epibionts:  epibionts seem to attach to whales in tropical waters, most likely in Colombian waters. Avila I.C., L.M. Cuellar & J.R. Cantera. 2011. Crustaceans ectoparasites and epibionts of humpback whales, Megaptera novaeangliae (Cetacea: Balaenopteridae), in the Colombian Pacific. UNED Research Journal / Cuadernos de Investigación UNED 3 (2): 177-185. Isabel Cristina Avila Jiménez Biologist MSc. Cali, Colombia, South America E-mail: isabel_c_avila@yahoo.com